Systematic identification and distribution analysis of olefins in FCC slurry oil

In response to the chemical industry's eco-friendly and high-value-added requirements, FCC slurry oil (SO) has been used as a raw material for novel solid carbon materials. As one of the most important chemically active intermediates and products in the FCC process, olefins may have a significant impact on the quality of the carbon materials produced. However, the existence and distribution of olefins have not been discussed. In this paper, olefinic hydrocarbons were first innovatively identified as important compounds that do exist in SO, and their distributions in sub-fractions below 500 °C, classified with the types and carbon numbers, were analyzed. However, there are great limitations for the existing analytical methods in the distribution detection of olefins in the whole fractions of heavy oils. In order to solve this problem, a newly-developed analytical method has been developed. Two different separation techniques were implemented to separate SO into six sub-fractions and eight group compositions, according to boiling point and molecular polarity respectively, before the analysis of olefin distribution for higher accuracy. The proposed method has been further verified by the GC × GC-TOFMS method and proved to have superior reliability. The olefinic carbons in the fraction of 350–400 °C possess the highest content among the detected narrow fractions, up to 1.55%, which decreases gradually with the increase of boiling points, and the first three sub-fractions between 350–470 °C take most of the olefinic carbons in SO, reaching around 74%.